Tube clamp for flaring tool



Oct. 10, 1967 G. E. 'FRANCK 3,345,855

I TUBE CLAMP FOR FLARING TOOL Filed Jan. 7. 1965 '-'IIIII fnz/enib 7-;- G80 Lyell/ 312M United States Patent O 3,345,855 TUBE CLAMP FOR FLARING TOOL George E. Franck, Morton Grove, Ill., assignor to Imperial-Eastman Corporation, a corporation of Illinois Filed Jan. 7, 1965, Ser. No. 424,026 6 Claims. (Cl. 72317) ABSTRACT OF THE DISCLOSURE A tube flaring tool having a flaring cone and means for holding the end of the tube'to be flared. The tube holding means includes a support bar means having a cylindrical bore including an outer frusto-conical end surface and an inner end surface having an arcuate cross section tangent to the outer end surface and to the cylindrical bore surface to provide an improved connection of the flared end to the cylindrical tube as the result of axially urging the cone into the tube end.

This invention relates to flaring tools and in particular to tools for flaring the end of tubing such as metal tubing to provide an improved sealed coupling.

In one conventional form of tube coupling, the coupling elements are arranged to receive atube having an outwardly flared end portion. The flaring of the tube end is effected prior to the introduction thereof into the coupling by means of a suitable flaring tool. Flaring tools for this purpose are well known. However, the tools of the art have a number of disadvantages, such as causing undesirable deformation of the tube end during the flaring operation. In particular, a common problem arising in such flared tube ends is the cracking or breaking of the tube at the juncture of the flare with the cylindrical tube wall. One solution to this problem which has been proposed is to provide a flaring tube holder wherein the tube is unsupported at this juncture point during the flaring operation so as to attempt to preclude concentration of deformation forces at this area. This method of flaring, however, has not-proven completely satisfactory as it does not provide suitable rigid support of the tube to assure an accurate flare configuration.

The present invention comprehends an improved tube flaring tool wherein the tube holder is arranged to provide the highly desirable support of the tube along the entire length of the flare including the juncture thereof with the cylindrical portion of the tube, while yet effectively avoiding the undesirable stress concentrations attendant the use of the conventional known flaring tools.

Thus, a principal object of the present invention is the provision of a new and improved flaring tool.

Another object of the invention is the provision of such a flaring tool having new and improved means for supporting the tube during the flaring operation.

A further object of the invention is the provision of such a tube flaring tool wherein the supporting means is arranged to support the flared end of the tube along its entire length upon completion of the flaring operation.

Still another object of the invention is the provision of such a flaring tool including a support means formed of bar stock metal and having a cylindrical bore for holding the tube end and an outer flared end, said flared end being defined by a frusto-conical outer end surface 3,345,855 Patented Oct. 10, 1967 narrowing axially inwardly and an annular inner end surface of circular cross-section tangent to said outer end surface and said cylindrical bore.

Other objects and advantages of the invention will be apparent from the following description taken in connection with the accompanying drawing wherein:

FIGURE 1 is a perspective view of a flaring tool embodying the invention;

FIGURE 2 is an enlarged vertical section thereof taken substantially along the line 22 of FIGURE 1 and illustrating the arrangement of a tube end therein as upon completion of a flaring operation;

FIGURE 3 is a further enlarged fragmentary vertical section illustrating the arrangement of the flaring cone tube end and support means as upon completion of the flaring operation;

FIGURE 4 is a further enlarged diametric section illustrating the configuration of the support means bore; and

FIGURE 5 is a fragmentary plan view thereof.

In the exemplary embodiment of the invention as disclosed in the drawing, a flaring tool generally designated 10 is shown to comprise a yoke 11 having a bight portion 12 and spaced legs 13 and 14. A flaring cone 15 is mounted coaxially on one end of a threaded carrier 16 which is threadedly carried in the bight 12 of yoke 11. A suitable hand-le 17 is provided at the upper end of the carrier 16 for forcibly advancing the flaring cone 15 against the end of a tube 18 clampedly held in a pair of clamp bars 19 and 20 in coaxial alignment with the axis of the carrier 16. The clamp bars are provided with suitable bores 21 of differing diameter for receiving different diameter tubes and each has an outer or upper surface 29. The clamp bars are arranged to be brought forcibly together to clamp the tube end positively therein such as by bolt means 22.

Referring now more specifically to FIGURES 3 through 5, each of bores 21 is defined by a cylindrical inner surface portion 23 and an outwardly widening end surface portion 24 including an outermost frusto-conical surface 25 and an inner annular surface 26. As shown in FIG- URE 3, the surface portion 24 is preselected to have the flared portion 27 of the tube end 18 in full surface engagement with the outer end surface 24 at the completion of the flaring operation.

More specifically, the taper angle of the flaring cone 15, Le. the angle between the outer conical flaring surface and the axis of the cone, may be 37. The angle of the frusto-conical surface 25 to the axis of the bore 21 herein may be smaller, but preferably is approximately the same as that of the flaring cone, namely 37. The annular surface 26 is arcuate in cross-section, and as best seen in.

FIGURE 4 is preferably circular and tangent at its outer end to the frusto-conical surface 25 at point 28 and at its inner end to the cylindrical surface 23 at point 28. The radius of the cross-sectional curvature of surface 26 is preferably greater than the perpendicular distance of the point of tangency 28' from bar outer surface 29, and the perpendicular distance of the point of tangency 28' from bar outer surface 29 is preferably greater than the difference in the radial distance of the tangency points 28 and 28 from the axis of the respective bores 21. Thus, in the preferred form, the laterally outward extension of surface 26 up to the point of tangency 28 thereof with the flare 27 provides an improved high strength sealing flare providing improved coupling association With the known fittings. As the clamping bars 19 and 20 are formed of bar stock with the portion 21 formed therein by suitable 5 machining operations, the tool is extremely simple and economical of construction while providing long, wear resistant life and providing the highly desirable improved flare formation discussed above.

Outer Diameter of Tube 18 Diameter of outer end of surface (at upper bar surface 2 .224 290 359 .421 4. 84 656 Spacing of tangency point 28 (and cent of curvature of surface 26) below upper bar surface 29 118 120 130 .130 130 .184 Radius of arcuate cross-section of surface 26 143 .144 156 156 156 .221 Difference between radius of surface 23 and radius of tangency point 28 .025 .026 .028 028 .028 040 Some specifications require tubes to be flared to a 25 angle. Under these circumstances, the flaring cone of the flaring tool would have a 90 included angle and exam ples of bore configurations embodying the invention and having a 45 surface 25, for use with specific conventional tubes 18 are set forth in the following table:

30 in the appended claims.

Outer Diameter of Tube 18 Diameter of outer end of surface 25 (at upper bar surface 29) .232 .279 .342 .404 .498 .561 .623 .748 .916 1. 041 1. 157 1. 297 Spacing of tangency point 28 (and center of curvature of surface 26) below upper bar surface 29 .094 .083 .085 .087 .116 .119 .119 .119 .163 .163 .155 .168 Radius of arcuate cross-section of surface 26 .094 .083 .085 .087 116 119 .119 .119 163 163 155 168 Difference between radius of surface 23 and radius of tangency point 28 .028 .024 .025 .026 .034 .035 .035 .035 048 .048 .046 .050

In the illustrated embodiment, the bars 19 and 20 are I claim:

formed of bar stock metal, such as steel, by means of suitably shaped cutting tools providing the desired frustoconical portion 25 and arcuate portion 26 in the flaring surface 24.

In use, the flaring tool 10 is caused to provide a flare 27 in the tube end 18 by firstly inserting the tube end into the selected appropriate diameter bore 21 defined by the clamp bars 19 and 20, the bolts 22 having been loosened sufliciently to permit the introduction of the tube end 'thereinto. The outer end of the tube is caused to be positioned slightly above the upper surface 29 of the clamp bars. The bolts 22 are then manipulated to draw the clamp bars forcibly together thereby to positively retain the tube end 18 in the bore 21. The yoke 11 is then positioned on the clamp bars, as shown in FIGURE 1, to dispose the flaring cone in coaxial alignment with the tube 18. The handle 17 is then manipulated to advance the flaring cone 15 downwardly coaxially into the end of the tube 18, thereby causing the end portion 27 of the tube to flare outwardly to the position shown in FIGURE 3. By virtue of the novel surface configuration provided, the flare 27 is caused to have surface engagement with surface 24 throughout its length. Further, by virtue of the improved arcuate cross-section of surface portion 26, excessive stress concentrations in the portion of the flare at the juncture thereof with the cylindrical undeformed tube .portion are effectively eliminated. Thus, the resultant 1. In a flaring tool provided with a flaring cone and means for moving the cone axially inwardly for flaring the end of a tube, means for holding the tube end coaxially of the cone during a flaring operation, comprising support bar means formed of bar stock metal and having a cylindrical bore for holding the tube end, said bore having an outer flared en-d opening through an outer surface of the bar, said bore end being defined by a frustoconical outer end surface narrowing axially inwardly and an annular inner end surface of arcuate cross-section tangent to said outer end surface and said cylindrical bore whereby the tube end is pressed by the flaring cone against said flared end surfaces over the entire length thereof.

2. The structure of claim 1 wherein the angle of the frusto-conical bore surface is the same as the taper angle of the flaring cone.

3. The structure of claim 1 wherein said inner end surface of the bore is circular in cross-section.

4. The structure of claim 1 wherein said inner end surface of the bore is circular in cross-section and the radius of curvature of said inner end surface is greater than the spacing of the center of curvature thereof inwardly of said bar outer surface.

5. The structure of claim 1 wherein the difference between the radius of the cylindrical bore and the radius of the line of tangency of said annular surface with said frusto-conical surface is small.

6. In a flaring tool provided with a flaring cone and means for moving the cone axially inwardly for flaring the end of a tube, means for holding the tube end coaxially of the cone during a flaring operation, comprising support bar means formed of bar stock metal and having a cylindrical bore for holding the tube end, said bore having an outer flared end defined by a frusto-conical outer end surface narrowing axially inwardly and an annular inner end surface of circular cross-section tangent to said outer end surfaces and said cylindrical bore, is arcuate angle of said inner end surface being substantially equal to the angle of said frusto-conical outer end surface to the axis of the cylindrical bore.

References Cited UNITED STATES PATENTS Lovekin 721 17 Havey 72-117 Hatton 72-318 X Mueller et a1 723 18 Wilkins 72--318 X Kellems 72317 10 CHARLES W. LANHAM, Primary Examiner.

E. SUTTON, Assistant Examiner. 

1. IN A FLARING TOOL PROVIDED WITH A FLARING CONE AND MEANS FOR MOVING THE CONE AXIALLY INWARDLY FOR FLARING THE END OF A TUBE, MEANS FOR HOLDING THE TUBE END COAXIALLY OF THE CONE DURING A FLARING OPERATION, COMPRISING SUPPORT BAR MEANS FORMED OF BAR STOCK METAL AND HAVING A CYLINDRICAL BORE FOR HOLDING THE TUBE END, SAID BORE HAVINF AN OUTER FLARED END OPENING THROUGH AN OUTER SURFACE OF THE BAR, SAID BORE END BEING DEFINED BY A FRUSTOCONICAL OUTER END SURFACE NARROWING AXIALLY INWARDLY AND AN ANNULAR INNER END SURFACE OF ARCUATE CROSS-SECTION TANGENT TO SAID OUTER END SURFACE AND SAID CYLINDRICAL BORE WHEREBY THE TUBE END IS PRESSED BY THE FLARING CONE AGAINST SAID FLARED END SURFACES OVER THE ENTIRE LENGTH THEREOF. 